Field of the Invention
The present invention relates to wireless communications, and more particularly, to a method of performing a hybrid automatic repeat request (HARQ) in a wireless communication system, and a wireless device using the method.
Related Art
Long term evolution (LTE) based on 3rd generation partnership project (3GPP) technical specification (TS) release 8 is a promising next-generation mobile communication standard. Recently, LTE-advanced (LTE-A) based on 3GPP TS release 10 supporting multiple carriers is under standardization.
As disclosed in 3GPP TS 36.211 V10.2.0 (2011-06) “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation (Release 10)”, a physical channel of the 3GPP LTE/LTE-A can be classified into a downlink channel, i.e., a physical downlink shared channel (PDSCH) and a physical downlink control channel (PDCCH), and an uplink channel, i.e., a physical uplink shared channel (PUSCH) and a physical uplink control channel (PUCCH).
Since the PDCCH is monitored on the basis of blind decoding, it is important to acquire control information by rapidly decoding the PDCCH. A time required to decode data on a specific channel is called a processing time, which has a great effect on a design of an operation requiring a signal exchange between a base station and a user equipment, similarly to a hybrid automatic repeat request (HARQ).
A channel state may vary depending on a propagation delay. In a wireless communication system, a timing advance (TA) is set to adjust an uplink synchronization of each wireless device, by considering the propagation delay. This is to advance uplink transmission by the TA in a wireless device which experiences the propagation delay.
As a required cell coverage is increased, the TA value is also increased. Therefore, a processing time required for decoding may not be ensured due to the advanced uplink transmission.